A more thorough explanation:

A suspicious character is someone who is believed to be involved in criminal activity and is therefore viewed with suspicion by law enforcement officials. In some states, a person who is strongly suspected or known to be a habitual criminal may be arrested or required to give security for good behavior.

• A man who is seen lurking around a neighborhood at night, peering into windows and trying to open doors, may be considered a suspicious character.
• A woman who is known to have a history of theft and is caught shoplifting in a store may also be considered a suspicious character.

These examples illustrate how a person's behavior or past actions can lead to them being viewed as a suspicious character. Law enforcement officials may keep a closer eye on individuals who exhibit suspicious behavior or have a history of criminal activity.